In the immediate postwar period (1946), the captured German A-4/V-2 rocket
was used in the United States not only for general rocket research, but also
for high-altitude scientific experiments. However, this large cumbersome
rocket was far from the ideal for relatively low-cost sounding rockets, and as
early as January 1946 it was planned to create a purpose-built research
rocket. The new rocket was to be based on the RTV-G-1 WAC Corporal
research vehicle, which was tested at that time by the U.S. Army. The sounding
rocket program was managed by the U.S. Navy Bureau of Ordnance (BuOrd), and in
May 1946, BuOrd awarded a development contract for the RTV-8 (changed
to RTV-N-8 in early 1948) Aerobee to Aerojet General. The first
live-firing of an Aerobee occurred in November 1947, and by 1950 the
Aerobee was in wide use by U.S. military research agencies.

The Aerobee was a single-stage liquid-fueled spin-stabilized rocket,
which used a solid-propellant rocket motor as a booster. Because initial
acceleration was relatively slow, it was launched in a high launch tower,
which guided the rocket until the fins would take effect. The booster was
jettisoned after burnout 2.5 seconds into the flight. The original Aerobee
could reach an apogee of about 120 km (75 miles) with a payload of about 68 kg
(150 lb). The nose cone containing the telemetry transmitter and the
scientific payload was recoverable and returned to earth on a parachute.

There were a multitude of versions of the basic Aerobee. The
original RTV-N-8, which was also known by Aerojet's designation XASR-1, used
an 11.5 kN (2600 lb) thrust sustainer. It was soon followed by the XASR-2,
which was designated RTV-A-1 by the Air Force and RTV-N-10 by
the Navy. The XASR-2 used helium pressurization instead of air pressurization
for the sustainer engine, and first flew in late 1949. The RTV-A-1a/RTV-N-10a
used an Aerojet AJ10-25 sustainer with 18 kN (4100 lb) thrust, but shorter
duration. The USAF also tested a few examples each of the RTV-A-1b
(using the original 11.5 kN engine with chemical pressurization), the
RTV-A-1c (as -1a, but launched without booster) and the RTV-A-1d
(using the 18 kN engine of the -1a with chemical pressurization, and launched
without booster). Other Navy models were the experimental RTV-N-10b
(using the AJ10-24 engine, a variant of the -10a's engine with a higher
specific impulse) and the RTV-N-10c (production variant of the -10b,
using an AJ10-27 sustainer). The USAF's production version of the
AJ10-24/RTV-N-10b was the AJ10-34, which did not get any designation.

In 1955, the USAF's RTV-A-1 rockets were re-designated in the X-8
series:

Old Designation

New Designation

RTV-A-1

X-8

RTV-A-1a

X-8A

RTV-A-1b

X-8B

RTV-A-1c

X-8C

RTV-A-1d

X-8D

The first major improvement of the basic Aerobee was the Aerobee-Hi,
which was developed from late 1952 and first flew in 1955. It had a longer
propellant tank, new materials in the rocket engine for higher efficiency, and
larger fins for improved stability. Initially two different variants were
built for USAF and U.S. Navy, the Air Force-Hi (which didn't use any
formal designation, except for the general project designator MX-1961)
and the RTV-N-13 (later RV-N-13) Navy-Hi. The Air
Force-Hi could loft a payload of 68 kg (150 lb) to about 240 km (150
miles), while the slightly longer Navy-Hi could reach 270 km (170
miles). There were several different Aerobee-Hi sustainer engine
configurations, known as AJ11-6, AJ11-18, AJ11-20, AJ11-21, AJ11-25 and
AGVL-0113C/F/H/I. The variants of the Navy-Hi were designated
RV-N-13a, RV-N-13b (with an AJ11-21 motor) and RV-N-13c. In
1959, the name Aerobee 150 was assigned by NASA to a "standarized"
Aerobee-Hi, which was a slightly modified Air Force-Hi. The last of
the variants of the original Aerobee was the Aerobee 150A, which
was a 150 with changed internal tank arrangement and four instead of
three fins on booster and sustainer.

Click on Picture to enlarge

RV-N-13 (PWN-2A) (without booster)

Aerobee 150 (without booster)

In April 1959, the USAF, at the request of the Air Force Cambridge Research
Center (AFCRC), allocated the formal research missile designation XRM-84
to an Aerobee-Hi configuration with the Aerojet AJ11-21 sustainer. This
was very similar (and possibly identical) to the RV-N-13b Navy-Hi. In
June 1963 the XRM-84 was redesignated as PWN-2A, but use of the
Aerobee family by the USAF ended at some time in the mid-1960s.

In total, more than 800 examples of the first Aerobee versions
(basic Aerobee, Aerobee-Hi and Aerobee 150/150A) were
built and flown by the U.S. military services and NASA between 1947 and 1985
(when the last Aerobee 150 was launched by NASA). It was the first
American general purpose high-altitude sounding rocket. It's most serious
drawback was the liquid-fueled sustainer engine, and the need for a relatively
large launch tower. Therefore it was not suitable for mass firings (many
rockets from a single location within a relatively short time frame) or for
launches in remote locations or from ships. For these purposes, in the
mid-1950s solid-fueled sounding rockets began to appear, which used many
multi-stage combinations of surplus and new solid-rocket boosters. One of
these, which was also used by the U.S. military, was the Nike-Cajun
(XRM-85/PWN-3). The Aerobee itself was developed into several enlarged
rockets like the Aerobee 170, Aerobee 300 and Aerobee 350.